The spine is a flexible column formed of a plurality of bones called vertebrae. The vertebrae are hollow and piled one upon the other, forming a strong hollow column for support of the cranium and trunk. The hollow core of the spine houses and protects the nerves of the spinal cord. The different vertebrae are connected to one another by means of articular processes and intervertebral, fibrocartilaginous bodies. Various spinal disorders may cause the spine to become misaligned, curved, and/or twisted or result in fractured and/or compressed vertebrae. It is often necessary to surgically correct these spinal disorders.
Various techniques are known for performing minimal-invasive discectomy. Most commonly, conventional cutting and manipulation tools are used under endoscopic control to sever disc tissue and remove it through a working channel. This approach is slow and tedious, particularly given limitations on the size of incision, and the risk of damage to the dural sac or nerve roots. Tools that use cutting and suction commonly require cleaning, sanitizing, and maintenance that increases costs associated with the procedures.
U.S. Patent Application Publication No. 2007/0149990 to Palmer et al. proposes a tissue removal instrument in which an elongated hollow device is formed from shape-memory materials that is biased to a predefined coiled form. The device has lateral cutting openings into which tissue is meant to be drawn under the influence of suction. The device is not sufficiently rigid to define a predictable path, and is described as loosening, tearing, or disrupting tissue within the nucleus of the disc during insertion. The unpredictability of the path that will be followed by the Palmer device during insertion may lead to a risk of perforation and injury and may incur difficulty reaching some material. Additionally, the suction-based approach appears impractical for effective removal of material along a long narrow device with openings spaced along its length. The Palmer tool does not provide any direct volumetric control of the quantity of material removed. The Palmer tool also does not appear to provide removable or disposable material removing elements.
U.S. Patent Application Publication No. 2010/0262147 to Siegal et al. proposes a tissue removal device in which an elongated element is formed by a plurality of interconnected hollow segments connected by effective hinges. The elongated element assumes a material removing configuration in which a segment hinges to expose a cutting configuration of the segment. The hollow interior of the segment collects material during progressive formation of the material removing configuration. While the Siegal device provides a more predictable path and reduces the need for suction, its segments reduce flexibility making it difficult to reach some material. The device must be continually withdrawn from the surgical area to remove the material from the segments and does not appear to provide removable or disposable material removing elements.
There is therefore a need for a device for insertion into a body via an opening, and for removing material from within the body, which would follow a predefined path, provide flexibility to remove difficult to reach material, and reduce the frequency of insertion and removal of the device. There is also a need for a device that utilizes reduced cost and disposable elements.